Revisiting the indirect signs of a temporal bone fracture: air, air, everywhere

Background and purpose: The standard head CT protocol makes detection of a temporal bone fracture difficult. The purposes of our study are to revisit the finding of air in various locations around the temporal bone as an indirect sign of fracture and determine if findings could predict fracture pattern. Materials and methods: We searched the radiology reports for the keyword “temporal bone fracture.” We recorded the presence of air in multiple locations around the temporal bone and pneumocephalus, opacification of the mastoid air cells or the middle ear cavity, and dominant fracture pattern. Statistical analyses were performed using statistical software. Results: A total of 135 patients (mean age 40 ± 20.1 years, 101 male, 34 female, range 1–91) had 152 fractures. At least one indirect finding was present in 143 (94.1%) fractures. Air was present adjacent to the styloid process in 94 (61.8%), in the temporomandibular joint in 80 (52.6%), adjacent to the mastoid process in 57 (37.5%), and along the adjacent dural venous sinus in 33 (21.7%) fractures. Mastoid opacification was present in 139 (91.4%) fractures. Opacification of the middle ear cavity was present in 121 (79.6%) fractures. A complex fracture significantly and positively correlated with pneumocephalus. Conclusion: In the setting of trauma, air around the temporal bone and opacification of the mastoid air cells or middle ear cavity should prompt consideration of a temporal bone fracture even if the fracture line is not visible. The presence of pneumocephalus predicts a higher chance of complex fracture pattern.